How to resolve the algorithm Yahoo! search interface step by step in the AArch64 Assembly programming language
Published on 12 May 2024 09:40 PM
How to resolve the algorithm Yahoo! search interface step by step in the AArch64 Assembly programming language
Table of Contents
Problem Statement
Create a class for searching Yahoo! results. It must implement a Next Page method, and read URL, Title and Content from results.
Let's start with the solution:
Step by Step solution about How to resolve the algorithm Yahoo! search interface step by step in the AArch64 Assembly programming language
Source code in the aarch64 programming language
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program yahoosearch64.s */
/* access RosettaCode.org and data extract */
/* use openssl for access to port 443 */
/* test openssl : package libssl-dev */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ TAILLEBUFFER, 500
.equ SSL_OP_NO_SSLv3, 0x02000000
.equ SSL_OP_NO_COMPRESSION, 0x00020000
.equ SSL_MODE_AUTO_RETRY, 0x00000004
.equ SSL_CTRL_MODE, 33
.equ BIO_C_SET_CONNECT, 100
.equ BIO_C_DO_STATE_MACHINE, 101
.equ BIO_C_SET_SSL, 109
.equ BIO_C_GET_SSL, 110
.equ LGBUFFERREQ, 512001
/*********************************/
/* Initialized data */
/*********************************/
.data
szMessDebutPgm: .asciz "Début du programme. \n"
szRetourLigne: .asciz "\n"
szMessFinOK: .asciz "Fin normale du programme. \n"
szMessErreur: .asciz "Erreur !!!"
szMessExtractArea: .asciz "Extraction = "
szNomSite1: .asciz "search.yahoo.com:443" // host name and port
szLibStart: .asciz ">Rosetta Code" // search string
szNomrepCertif: .asciz "/pi/certificats"
szRequete1: .asciz "GET /search?p=\"Rosettacode.org\"&b=1 HTTP/1.1 \r\nHost: search.yahoo.com\r\nConnection: keep-alive\r\nContent-Type: text/plain\r\n\r\n"
/*********************************/
/* UnInitialized data */
/*********************************/
.bss
.align 4
sBufferreq: .skip LGBUFFERREQ
szExtractArea: .skip TAILLEBUFFER
stNewSSL: .skip 200
/*********************************/
/* code section */
/*********************************/
.text
.global main
main:
ldr x0,qAdrszMessDebutPgm
bl affichageMess // start message
/* connexion host port 443 and send query */
bl envoiRequete
cmp x0,#-1
beq 99f // error ?
bl analyseReponse
ldr x0,qAdrszMessFinOK // end message
bl affichageMess
mov x0, #0 // return code ok
b 100f
99:
ldr x0,qAdrszMessErreur // error
bl affichageMess
mov x0, #1 // return code error
b 100f
100:
mov x8,EXIT // program end
svc 0 // system call
qAdrszMessDebutPgm: .quad szMessDebutPgm
qAdrszMessFinOK: .quad szMessFinOK
qAdrszMessErreur: .quad szMessErreur
/*********************************************************/
/* connexion host port 443 and send query */
/*********************************************************/
envoiRequete:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! // save registers
stp x4,x5,[sp,-16]! // save registers
//*************************************
// openSsl functions use *
//*************************************
//init ssl
bl OPENSSL_init_crypto
bl ERR_load_BIO_strings
mov x2, #0
mov x1, #0
mov x0, #2
bl OPENSSL_init_crypto
mov x2, #0
mov x1, #0
mov x0, #0
bl OPENSSL_init_ssl
cmp x0,#0
blt erreur
bl TLS_client_method
bl SSL_CTX_new
cmp x0,#0
ble erreur
mov x20,x0 // save contex
ldr x1,iFlag
bl SSL_CTX_set_options
mov x0,x20 // contex
mov x1,#0
ldr x2,qAdrszNomrepCertif
bl SSL_CTX_load_verify_locations
cmp x0,#0
ble erreur
mov x0,x20 // contex
bl BIO_new_ssl_connect
cmp x0,#0
ble erreur
mov x21,x0 // save bio
mov x1,#BIO_C_GET_SSL
mov x2,#0
ldr x3,qAdrstNewSSL
bl BIO_ctrl
ldr x0,qAdrstNewSSL
ldr x0,[x0]
mov x1,#SSL_CTRL_MODE
mov x2,#SSL_MODE_AUTO_RETRY
mov x3,#0
bl SSL_ctrl
mov x0,x21 // bio
mov x1,#BIO_C_SET_CONNECT
mov x2,#0
ldr x3,qAdrszNomSite1
bl BIO_ctrl
mov x0,x21 // bio
mov x1,#BIO_C_DO_STATE_MACHINE
mov x2,#0
mov x3,#0
bl BIO_ctrl
// compute query length
mov x2,#0
ldr x1,qAdrszRequete1 // query
1:
ldrb w0,[x1,x2]
cmp x0,#0
add x8,x2,1
csel x2,x8,x2,ne
bne 1b
// send query
mov x0,x21 // bio
// x1 = address query
// x2 = length query
mov x3,#0
bl BIO_write // send query
cmp x0,#0
blt erreur
ldr x22,qAdrsBufferreq // buffer address
2: // begin loop to read datas
mov x0,x21 // bio
mov x1,x22 // buffer address
ldr x2,qLgBuffer
mov x3,#0
bl BIO_read
cmp x0,#0
ble 4f // error ou pb server
add x22,x22,x0
sub x2,x22,#8
ldr x2,[x2]
ldr x3,qCharEnd
cmp x2,x3 // text end ?
beq 4f
mov x1,#0xFFFFFF // delay loop
3:
subs x1,x1,1
bgt 3b
b 2b // loop read other chunk
4: // read end
//ldr x0,qAdrsBufferreq // to display buffer response of the query
//bl affichageMess
mov x0, x21 // close bio
bl BIO_free_all
mov x0,#0
b 100f
erreur: // error display
ldr x1,qAdrszMessErreur
bl afficheErreur
mov x0,#-1 // error code
b 100f
100:
ldp x4,x5,[sp],16 // restaur 2 registers
ldp x2,x3,[sp],16 // restaur 2 registers
ldp x1,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
qAdrszRequete1: .quad szRequete1
qAdrsBufferreq: .quad sBufferreq
iFlag: .quad SSL_OP_NO_SSLv3 | SSL_OP_NO_COMPRESSION
qAdrstNewSSL: .quad stNewSSL
qAdrszNomSite1: .quad szNomSite1
qAdrszNomrepCertif: .quad szNomrepCertif
qCharEnd: .quad 0x0A0D0A0D300A0D0A
qLgBuffer: .quad LGBUFFERREQ - 1
/*********************************************************/
/* response analyze */
/*********************************************************/
analyseReponse:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! // save registers
ldr x0,qAdrsBufferreq // buffer address
ldr x1,qAdrszLibStart // key text address
mov x2,#2 // occurence key text
mov x3,#-11 // offset
ldr x4,qAdrszExtractArea // address result area
bl extChaine
cmp x0,#-1
beq 99f
ldr x0,qAdrszMessExtractArea
bl affichageMess
ldr x0,qAdrszExtractArea // résult display
bl affichageMess
ldr x0,qAdrszRetourLigne
bl affichageMess
b 100f
99:
ldr x0,qAdrszMessErreur // error
bl affichageMess
mov x0, #-1 // error return code
b 100f
100:
ldp x2,x3,[sp],16 // restaur 2 registers
ldp x1,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
qAdrszLibStart: .quad szLibStart
qAdrszExtractArea: .quad szExtractArea
qAdrszMessExtractArea: .quad szMessExtractArea
qAdrszRetourLigne: .quad szRetourLigne
/*********************************************************/
/* Text Extraction behind text key */
/*********************************************************/
/* x0 buffer address */
/* x1 key text to search */
/* x2 number occurences to key text */
/* x3 offset */
/* x4 result address */
extChaine:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! // save registers
stp x4,x5,[sp,-16]! // save registers
stp x6,x7,[sp,-16]! // save registers
mov x5,x0 // save buffer address
mov x6,x1 // save key text
// compute text length
mov x8,#0
1: // loop
ldrb w0,[x5,x8] // load a byte
cmp x0,#0 // end ?
add x9,x8,1
csel x8,x9,x8,ne
bne 1b // no -> loop
add x8,x8,x5 // compute text end
mov x7,#0
2: // compute length text key
ldrb w0,[x6,x7]
cmp x0,#0
add x9,x7,1
csel x7,x9,x7,ne
bne 2b
3: // loop to search niéme(x2) key text
mov x0,x5
mov x1,x6
bl rechercheSousChaine
cmp x0,#0
blt 100f
subs x2,x2,1
ble 31f
add x5,x5,x0
add x5,x5,x7
b 3b
31:
add x0,x0,x5 // add address text to index
add x3,x3,x0 // add offset
sub x3,x3,1
// and add length key text
add x3,x3,x7
cmp x3,x8 // > at text end
bge 98f
mov x0,0
4: // character loop copy
ldrb w2,[x3,x0]
strb w2,[x4,x0]
cbz x2,99f // text end ? return zero
cmp x0,48 // extraction length
beq 5f
add x0,x0,1
b 4b // and loop
5:
mov x2,0 // store final zéro
strb w2,[x4,x0]
add x0,x0,1
add x0,x0,x3 // x0 return the last position of extraction
// it is possible o search another text
b 100f
98:
mov x0,-1 // error
b 100f
99:
mov x0,0
100:
ldp x6,x7,[sp],16 // restaur 2 registers
ldp x4,x5,[sp],16 // restaur 2 registers
ldp x2,x3,[sp],16 // restaur 2 registers
ldp x1,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
/******************************************************************/
/* search substring in string */
/******************************************************************/
/* x0 contains address string */
/* x1 contains address substring */
/* x0 return start index substring or -1 if not find */
rechercheSousChaine:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! // save registers
stp x4,x5,[sp,-16]! // save registers
stp x6,x7,[sp,-16]! // save registers
mov x2,#0 // index position string
mov x3,#0 // index position substring
mov x6,#-1 // search index
ldrb w4,[x1,x3] // load first byte substring
cbz x4,99f // zero final ? error
1:
ldrb w5,[x0,x2] // load string byte
cbz x5,99f // zero final ? yes -> not found
cmp x5,x4 // compare character two strings
beq 2f
mov x6,-1 // not equal - > raz index
mov x3,0 // and raz byte counter
ldrb w4,[x1,x3] // and load byte
add x2,x2,1 // and increment byte counter
b 1b // and loop
2: // characters equal
cmp x6,-1 // first character equal ?
csel x6,x2,x6,eq // yes -> start index in x6
add x3,x3,1 // increment substring counter
ldrb w4,[x1,x3] // and load next byte
cbz x4,3f // zero final ? yes -> search end
add x2,x2,1 // else increment string index
b 1b // and loop
3:
mov x0,x6 // return start index substring in the string
b 100f
99:
mov x0,-1 // not found
100:
ldp x6,x7,[sp],16 // restaur 2 registers
ldp x4,x5,[sp],16 // restaur 2 registers
ldp x2,x3,[sp],16 // restaur 2 registers
ldp x1,lr,[sp],16 // restaur 2 registers
ret // return to address lr x30
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
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